Question:
Name the various plant hormones. Also give their physiological effects on plant growth and development. (CCE 2016)
Solution:
Five types — auxin, gibberelin, cytokinin, ethylene and abscisic acid.
Auxin: Cell enlargement, root formation, apical dominance, inhibition of abscission, fruit growth.
Gibberellin: Growth in stem and leaves, higher fruit yield, overcoming dormancy.
Cytokinin: Essential for cell division, differentiation, prevention of senescence and overcoming apical dominance.
Ethylene: Promotes transverse growth, fruit ripening and overcoming dormancy of some parts.
Abscisic Acid (ABA): Induces dormancy, senescence and abscission, checking excessive activity of growth promoting hormones, closure of
stomata under water stress.